A vast array of gene polymorphisms have been described, and further discovery of these gene variants will continue as the human genome is defined. Therefore, selection of a single polymorphism to investigate in relation to disease evolution or outcome must be motivated by specific physiologic, pathophysiologic, or epidemiologic associations. A significant gene polymorphism may result in an alteration of protein function, or be associated with disease incidence or outcome. Prevalence of the polymorphism in the general population is of extreme importance, as it must be common enough to warrant interest in its clinical impact. The polymorphism of the gene encoding for the enzyme adenosine monophosphate deaminase 1 results in an abnormal protein necessary in skeletal muscle metabolism. While its physiologic effects are not completely understood, it has been associated with improved morbidity and mortality in patients with cardiovascular disease.